Chapter 10 - Cell Respiration

Question 1

ATP

Answer 1

Adenosine Triphosphate
-RNA nucleotide
-adenine nucleoside triphosphate
(1 adenine base + 1 ribose sugar + 3 phosphate groups)
-release 7.2 kcal when 1 mole of phosphoanhydride bridge is hydrolyzed

Question 2

Aerobic respiration

Answer 2

Complete breakdown of glucose using O2 as the final e- acceptor
Result: CO2, H2O and 32 ATP

Glycolysis (cyt) => pyruvate oxidation (mit. Matrix) => TCA cycle (mit. matrix) => oxidative phosphorylation (mit. cristae)

Question 3

Fermentation

Answer 3

-partial decomposition of organic fuel in the absence of O2 (no ETC)

Largely divided into:

1) Alcohol fermentation (yeasts/plants) CO2 release
2) Lactic acid fermentation (animals/bacteria)

Question 4

Alcohol fermentation

Answer 4

-type of anaerobic respiration
glucose (glycolysis) => 2 pyruvate => 2 acetaldehyde => 2 ethanol

• acetaldehyde serves as final e- acceptor
• result: 2 ATP, ethanol, CO2

Question 5

Lactic acid fermentation

Answer 5

-type of anaerobic respiration
glucose (glycolysis) => 2 pyruvate => 2 lactate

• pyruvate serves as final e- acceptor
• result: 2 ATP, lactate

Question 6

Anaerobes

Answer 6

• do not require O2 for survival
  1) obligate anaerobes
• only carry out fermentation & anaerobic respiration
• can’t survive in O2 environment
  2) facultative anaerobes
• carry out both aerobic & anaerobic respiration (fermentation)
• can survive in O2 environment
  e. g. yeast

Question 7

Cellular respiration

Answer 7

catabolic breakdown of glucose, releasing energy (ATP) in the process

C6H12O6 + 6O2 => 6CO2 + 6H2O + 32 ATP

• glucose oxidized, used as reducing agent
• O2 reduced, used as oxidizing agent

Question 8

NAD

Answer 8

Nicotinamide Adenine Nucleotide

Question 9

FAD

Answer 9

Flavin Adenine Dinucleotide

Question 10

Anaerobic respiration

Answer 10

partial breakdown of glucose without using O2 as the final e- acceptor
-some use sulfate (SO4 2-) or nitrate (NO3 -) as the final e- acceptor

Question 11

Sequence of e- transport in aerobic respiration

Answer 11

glucose => NAD+ / FAD+ => Electron transport chain => O2 (final e- acceptor, produces H2O)

Question 12

Stages of aerobic respiration

Answer 12

1) Glycolysis (cyt)
2) Pyruvate oxidation (mit. matrix)
3) TCA cycle (mit. matrix)
4) Oxidative phosphorylation (mit. cristae membrane)

Question 13

Results of each stage in aerobic respiration

Answer 13

1) Glycolysis (cyt)
=2 pyruvate, 2 ATP, 2 NADH, 2H2O
2) Pyruvate oxidation (mit. matrix)
=Acetyl CoA, NADH, CO2
3) TCA cycle (mit. matrix)
=3NADH, 2CO2, 1 ATP, 1 FADH
4) Oxidative phosphorylation (mit. cristae membrane)
=ATP formation, H2O

Question 14

Glycolysis

Answer 14

1st step of respiration (for both anaerobic & aerobic)

• oldest, most widespread catabolic pathway
• occurs in cytoplasm of cell

final product:
4 ATP (net gain of 2 ATP)
2 pyruvate
2H2O
2NADH + 2H+

Phosphofructokinase - allosteric enzyme
-substrate = phosphofructose

Question 15

Pyruvate oxidation

Answer 15

2nd step of aerobic respiration
-occurs in mitochondrial matrix

pyruvate => acetyl CoA
1) decarboxylation (removal of CO2)
2) NAD+ => NADH + H+ (pyruvate dehydrogenase)
3) help from coenzyme A
final product: acetyl CoA

pyruvate dehydrogenase helps reaction of NAD+ + H+ => NADH

Coenzyme A

• derived from vitamin B5
• connects pyruvate to oxaloacetate

Question 16

TCA cycle (citric acid cycle)

Answer 16

cycle of oxaloacete - oxaloacetate.

occurs in matrix of mitochondira (eukaryote)

cytosol in prokaryote.

from 1 acetyl CoA = 3NADH, 1FADH, 2CO₂, 1ATP

Question 17

Oxidative phosphoration

Answer 17

occurs on inner membrane of mitochondria

use electron transport chain to generate proton motive force.

(H⁺ are pumped out to intermembrane space) = generating proton motive force.

final electron acceptor is O₂. -> forming H₂O

lastly, ATP synthase generate ATP, using already generated proton motive force.

1NADH = 2.5 ATP

1FADH = 1.5 ATP

during oxidative phosphoration, 28ATP are generated.